this is "nightline." tonight, labor of love. how far would you go for a stranger? >> unselfish thing anyone can ever do. >> they've never met, but they are about to save each other's lives. >> meeting the patients and them being so -- i'm getting emotional. being so happy. >> selfless men and women risking everything to go under the knife. and we're inside the o.r., as a record-breaking transplant chain is under way. plus, no rope, no safety equipment, and no turning back. >> i stood there for a minute being like, what have i done? >> meet the extreme mountain climber who has built a career by defying death. but first, the "nightline" five. >> when heartburn comes creeping up on you, fight back with release so smooth, it's fast. tums smoothies starting dissolving the instant it touches your tongue.

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good evening and happy thanksgiving. thank you for joining us. why would a straning of strange made sacrifices to give the gift of life? it could give hope to countless others in need, or come with grave con consequencsequences. "nightline's" juju chang is headed into the o.r. >> reporter: it's 6:00 a.m. these patients are strangers,

but they're about to save each other's lives. >> i'm not worried about me. i'm worried about my baby. >> reporter: if all goes well, they'll be forever linked. it's the longest living kidney donor chain. 21 kidneys, 21 lives transformed. >> we have seven transplants planned this week. >> reporter: and this is dr. jamie lock. she's both surgeon and match maker at the university of alabama at birmingham medical center. she's helping expand the pool of donors and recipients by creating chains of living donors. it works like this. a recipient needs someone, a spouse, a parent, a friend, willing to donate a kidney to a complete stranger, so that they can receive a kidney from a stranger in return. >> where the magic happens and the my stroe lives, right here. >> reporter: by dr. lock's side is lead nurse katie who poors over patient data.

>> i go through this every day and just click it and it keeps coming up no matches. so, what i have to do is go through and make lists for myself. >> reporter: this is basic little your hay tack and you are looking for the needle in there. >> yeah. >> reporter: her cramped office and tidy white boards tell the story of just how dif ult it is to find a workable match. so, what drives you? >> this. just -- meeting the patients and them being so -- i'm getting emotional. being so happy. >> reporter: katie is a hard core o.r. nurse. but getting to know these patients has softened her heart. >> at my ol job, i was involved solely in the o.r. and they were just abdomens. now, they're really people. >> hoi are you? >> reporter: people like 18-year-old high school student kaitlyn. >> it's going to kind of go right about here, okay? >> reporter: a year ago, kaitlyn, a rising high school senior, and a black belt in

karate suddenly fell seriously ill and had few options. >> either to stay on dialysis for the rest of my life or to get the transplant. >> reporter: kaitlyn joined the ranks of the more than 100,000 americans in desperate need of a kidney transplant. for many, the wait for a deceased donor kidney could last 8 to 10 years. >> she's hooked up to the dialysis machine. every night. every night of her le. >> reporter: earl was actually a match for his daughter, but by joining the chain, kaitlyn will get a much younger kidney from a stranger. and her dad, earl, will donate one of his in kaitlyn's honor. >> i prayed to god that he would send an answer for my child and he has. how can i refuse someone else? >> any questions or anything? >> reporter: the day before surgery who that someone is remains a mystery. >> it's very important that we kind of keep everything completely anonymous going in, but usually the day after, when

people are up for it, they usually kind of meet up. >> reporter: in fact, all along this hospital floor, others are curious, too. like this donor, pastor derek lambert. >> i don't know if this is, you know, perhaps a young mother who is feared leaving her kids or a young man who is unable to provide for the needs of his family. >> reporter: he's donating to a stranger so his friend and a deacon at his former church can get one in return. it's a moment worthy of a little prayer. >> so, father, we entrust this to you and we do so in the name of jesus, amen. >> amen. >> reporter: and just next door, though neither of them knows it is indeed a wife and mother of two, allison nel zone, is about to receive the pastor's gift of life. >> i think it's the most unselfish thing anyone can do. >> reporter: this young mom is getting the pastor's kidney because her cousin stepped forward and volunteered to donate on her behalf. >> people keep telling me how

brave i am and i keep saying, i don't think i'm brave at all. i think everybody would do this if they had the person that, like, if the right person needed it. >> reporter: courtney may be modest, but her mother is overwhelmed. >> i cannot believe that i've got such a good, loving daughter. >> reporter: and what they don't know is that cousin courtney's kidney is destined to provide a fresh, new start for high schooler kaitlyn. >> tomorrow, we start a new chapter in her life. >> reporter: it's dawn on the day of the surgery. dr. lock and katie check in on the two donors just minutes before they head into surgery. >> happy kidney donation day. >> i kept thinking, well, i'll get nervous as it gets closer. you know, i'll start to worry when it's almost here and it doesn't get much closer than this and i'm still good. >> the donors will go into surgery first. it's a carefully timed choreography to ensure the

kidney spends as little time as possible outside a human body. by 7:30, dr. lock is scrubbing in to remove pastor derek's healthy kidney. next door, cousin courtney is being wheeled in to have one of hers removed, as well. like any surgery, removing a kidney is not without risk or potential complications, but most people can live a completely normal life with just one kidney. while the precious organs are being removed, the people who are about to receive them have come down to pre-op. >> since this morning i feel very calm. >> happy kidney day. >> thank you. >> reporter: down the hall, high schooler kaitlyn and her parents await. >> very excited. nervous. still excited. >> reporter: just after noon, dr. lock removes pastor decker's kidney and hands it off to a second surgical team. the precious cargo placed in this humble cooler for its quick journey down the hall to

allison. one down, one to go. with no time to lose, dr. lock goes to check on her next patient. >> y'all ready? >> her kidney is beautiful. very exciting. all right, see you in a little bit. >> okay. >> reporter: and minutes later, kaitlyn is wheeled back to the o.r. kaitlyn's new kidney arrive arr. it takes three hours to sew in the new kidney. and right away, it's doing its job. >> she's doing great. kidney looks absolutely gorgeous. started making lots of urine right on the table. >> thank you so much. >> you're welcome. >> reporter: the relief and gratitude are palpable. within 24 hours, high school student kaitlyn is taking her first shaky steps with her new kidney on board. down the hall, pastor derek is sitting up in a chair, minus a kidney, but his good spirits intact. what would you say to folks who are skeptical about, like, oh, i would never be as generous as pastor derek?

>> if we want someone to help us in our time of need, we have to be willing to help in their time of need. >> reporter: and kaitlyn's dad is once again optimistic. >> thinking about her future, being able to go back to coll e college, start dating boys again. doing all the things that an 18-year-old young adult should be able to do. >> reporter: what's barely registering is the fact that he's about to donate his own kid knee tomorrow to keep the chain going. donor chains like this one can potentially revolutionize the way those in need are matched with potential donors. but according to dr. lock, what's missing is one centralized system. >> if we could do that, then i think we would be really able to optimize living kidney donation in this country and we could begin to make a significant dent in the waiting list. >> reporter: these patients don't have to wait any longer. 24 hours after surgery, we're there as they're about to meet their mystery donors. >> i think why we're all here is so that we can meet each other.

you've got your kidney from mr. lambert. >> thank you. >> courtney came forward to donate in honor of allison, and she donated to an 18-year-old young woman who now can go back to getting back to life. >> thank you. >> this is our daughter. >> reporter: slowly, they share details about each other's lives. for pastor derek, his kidney went to a young mother, allison who is raising children similar in age to his own. >> we are grateful that his kidney will help you raise your children. >> thank you. >> turns out the other kidney went from one black belt in karate to another. >> i was hoping it would be her donor and it was. >> reporter: the doctors say you can go back to doing martial arts afterward? >> yeah, no more contact, but -- can't risk hurting the kidney we have left. >> reporter: it's a gift that must be taken good care of.

and a gift that will forever unite these patients, their families and the medical team that brought them together. >> you look into people's eyes and you see hope that wasn't there before. you see the promise of a future that they weren't sure they were going to have. >> our thanks to juju for that report. and to the university of alabama at birmingham. last week, they completed their 29th transplant. a donor? a member of pastor derek's former church. next, what kind of person climbs mountains with no safety gare? we're with one on his latest death-defying venture. can he make it? sorry to interrupt... i gotta take a sick day tomorrow. dads don't take sick days, dads take nyquil. the nighttime, sniffling, sneezing, coughing, aching, fever, best sleep with a cold, medicine. [coughing] hey amanda, sorry to bother you, but i gotta take a sick day. moms don't take sick days, moms take dayquil. the non drowsy, coughing,

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many of us like a thrill every now and again. maybe braving a roller coaster ride, hunkering down for a scary movie. none of that is in the same universe as what you're about to see. this is a man who climbs rock fashions with no safety equipment. here's abc's neal karlinsky. >> reporter: look closely. that red speck stuck to the wall defying death is alex. no rope, no safety equipment, no turning back. it's hard not to be nervous, even terrified looking straight down at him. he's an extreme free climber. this time, taking on mexico. the fact that his life is suspended by just a few toes, his fingertips and concentration galore is mind boggling. >> when you are so alone, you are focused whoon you're doing, or you are just empty and executing what you ahave to do.

>> reporter: he's a pretty mellow guy for a guy putting his life on the line all the time. >> here we are on the summit of moses. we just had a biblical experience. it's snowing. >> snowing quite hard. >> the wrath of god rained down upon us. epic snowstorm. >> reporter: fear, danger and death, the subjects everyone wants to know about, drive alex a bill nt nuts. >> i do the climbing without a rope, whatever. it looks crazy. wow, you're on the edge of a cliff. but seeing a photo of that doesn't give any indication of how likely i am to fall off. trucker boss the same thing. if you veer off the road, if they lose concentration for a few seconds and veer off the highway 80 miles an hour, they will die. but you know, do people consider that extremely risky? no. because, you know, the risk is quite small. >> reporter: you see it that way? you see the analogy to driving a

truck down the highway? >> i see all of life is an odds game, you know? everything you do has risk, so, you know, i mean, i choose my risks carefully. >> reporter: and he has. at 28, alex is easily regarded as perhaps the world's best mountain climber. he holds a number of speed records for climbing sheer faces in yosemite without ropes. but if you're going to see how he does it, you have to visit his office. the mountains. >> pull yourself up. >> reporter: i did. and can tell you climbing even a little with alex is a case of it looks a lot easier than it really is. wow, that was horrible. >> you did good. >> happy to be alive? >> reporter: yes, i'm happy to keep me alive. thanks for keeping me alive. barely. we tagged along with alex and his good friend and fellow insanely talented climber cedar.

>> i'm the king of the world! >> reporter: and a series of climbs. >> perfect. not too bad from here. good. >> oh, yeah. >> all right. summit one. not a bad view. >> yeah, go cedar, go. >> reporter: he's an accomplished professional climber in his own right. but even he occasional little worried about alex. >> he's an extremely accomplished athlete, but at the same time, there are things that he can't affordable. say a rock could break or maybe a bird dives out of a crack. had's playi i he's playing a game where the ultimate stake is to lose your life. >> reporter: alex insists he gets too much attention for what's called free soloing. going without ropes. arguing that 90% of his climbs are with ropes. but it's hard to argue with the impression people get watching a

person cling ropeless to a mountain. something that seems so impossible to most of us. one slip and it's all ov.. has your inner voice stopped you at certain times from going on? have you had that voice -- >> for sure there are tons of things i've gone to sol losolo just climbed back down and gone home. >> reporter: even alex has had his moments, fear fighting for a toe hold alongside him. >> that's one of the things where you feel sorry for yourself for a minute and then, you're like, well, i better pull it together because i'm standing on a blank face, you know? so, i stood there for a minute, being like, what have i done? and then i finished the climbing. >> reporter: being a professional mountain climber means s being a bit of a nomad. his sponsors pay him to climb the world's most beautiful mountains year round. he's even popped up in the occasional tv commercial for citibank. when he's in the u.s., he lives and travels out of his van.

>> it's a nice home. i got everything we need in here. i mean, i do have basically everything i own in here. >> reporter: his life is at once extreme and extremely simple. with his endorsements including north face, he makes a good living, but he says, he spends virtually nothing on himself. >> i'm making a peanut butter and jell little or ty tortilla . >> reporter: clif bars suddenly ended its relationship with alex and others, saying these forms of sport are pushing boundaries and taking the element of risk to a place where we are no longer willing to go. alex responded in a letter to "the new york times," calling it a shock that someone at clif bar seemed to have awakened suddenly and realized that climbing without a rope on vertical walls as high as 2,000 feet is dangerous. his fears, he says, are no different from the rest of us down on solid ground. >> i used to be scared of

speaking in public. i've gotten over it because of this stuff. >> reporter: during our time together, alex and cedar were in the middle of a grueling 700-mile bike and climbing trip, which including tops for alex's charitable foundation, providing solar panels to native american hopes without electricity. that trip is now a film. it's about as far from a 9:00 to 5:00 lifestyle as you can get, and alex, conquerer of mountains, has no intention of slowing down. >> th this is a job you can retire from? >> yeah, there are a lot of old climbers. you can go in the mountains your whole life and enjoy. it's awesome. i'm hoping to you, you know retire with grandkids and stuff. >> reporter: i'm neal karlinsky for "nightline" in mon ewement valley, utah. >> from his lips to god's ear. we'll be right back. the volkswagen golf was just named

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be sure to tune into "nightline" tomorrow night, when we find out if the man known as the plane whisperer can cure your fear of flying. plus, from above the earth to below it. imagine living entirely underground. for some, it's almost the only life they know. and we're heading down into their world. that's on "nightline" tomorrow night. thank you for watching abc news. tune into "good morning america" tomorrow and, as always, we're online at abcnews.com. good night, america.

jeezaloo, look at geoffrey. he's skipping. he's having fun, frank. then he should try curtseying. that's fun, too. he reminds me of you, raymond. i didn't do that, mom. yes, you did. i did not skip. to my loo.

this is boring. will you take me to the playground now, uncle robert? all right, for a few mites. but listen, there's plenty of monkey bars out there. not everyone has to climb on me. please? all right. why didn't you bring some cushions or something? this bench is killing me. it's crushing his brain. sure. thesseats don't bother you. hey, if you two can't get along, i'm gonna separate you.